Ignition Sensor Kit – Fits MerCruiser GM V6 & V8 (Replaces 87-91019A2, 87-892150Q02)

$37.00

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Ignition Sensor Kit – Fits MerCruiser GM V6 & V8 (Replaces 87-91019A2, 87-892150Q02) is backordered and will ship as soon as it is back in stock.

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Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Ignition Sensor Kit is a crucial component designed for MerCruiser V6 and V8 engines equipped with Thunderbolt IV & V electronic ignition systems, specifically covering models from 1981 to 1997. It ensures reliable spark timing, restoring engine performance and efficiency for a wide range of power ratings, including 4.3L, 5.0L, 5.7L, 7.4L, and 8.2L models.

This kit serves as a direct aftermarket replacement for Mercury/MerCruiser part numbers 87-892150Q02, 87-91019A3, 87-91019A2, and others, offering a reliable and cost-effective alternative to OEM parts.

Engineered as a direct-fit replacement for straightforward installation.
Constructed from glass-filled polyester for durability in harsh marine environments.
Includes essential lead wires and connectors for a complete setup.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Mercury/MerCruiser	87-892150Q02
Mercury/MerCruiser	87-892150A02
Mercury/MerCruiser	87-91019A3
Mercury/MerCruiser	87-91019A2
Mercury/MerCruiser	861780A2
Mercury/MerCruiser	861780K4
Mercury/MerCruiser	861780Q4
Mercury/MerCruiser	87-892150K02
Mercury/MerCruiser	892150A02
Mercury/MerCruiser	91019A6
Sierra	18-5116-1
Mallory	9-29804

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This sensor is designed for MerCruiser engines utilizing Thunderbolt IV and V ignition systems from approximately 1981 through 1997.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
MerCruiser	V6 4.3L	205	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	V8 5.0L	240-260	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	V8 5.7L	260-350	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	V8 7.4L	320-425	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	V8 8.2L	425-500	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	MR	350	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	MAG	350	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	ALPHA		4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	BRAVO		4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	454	450	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	465	465	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	502	500-525	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	575	575	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	600	600	4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition
MerCruiser	Gen VI		4-Stroke	1981–1997	87-91019A2	Thunderbolt IV & V ignition

Technical Specs

Product Type: Ignition Sensor Kit
Installation: Direct replacement
Housing Material: Glass-filled polyester
Connection: Lead wires with connectors
Other Technical Attributes: Designed for marine applications with corrosion resistance

What’s in the Box

1 x Ignition Sensor (Replaces 87-91019A2)
1 x Set of Lead Wires with Connectors
1 x Hardware Kit (mounting screws and fasteners)

Installation Notes

Disconnect the boat's battery before beginning work.
Locate the distributor and carefully remove the distributor cap and rotor.
Note the wiring configuration of the old ignition sensor before disconnecting it.
Remove the mounting screws holding the old sensor and lift it out.
Position the new sensor and secure it with the provided hardware.
Connect the new sensor's lead wires, matching the original configuration.
Reinstall the rotor and distributor cap.
Reconnect the battery and start the engine to test for proper operation.

Troubleshooting & FAQ

How do I know if my ignition sensor is failing?

Common signs of a failing ignition sensor include engine misfires, difficulty starting, stalling, rough idling, a noticeable loss of power, or the check engine light illuminating. These symptoms occur because the sensor is not sending accurate timing signals to the ignition module.

Is this sensor compatible with both Thunderbolt IV and V systems?

Yes, this ignition sensor kit is designed to be fully compatible with both MerCruiser Thunderbolt IV (T-IV) and Thunderbolt V (T-V) electronic ignition systems within the specified engine models and years (1981-1997).

Can I install this myself?

While installation is straightforward for those with mechanical experience, professional installation is always recommended to ensure proper timing, wiring, and to avoid potential damage. The process involves working with the engine's ignition system, which is critical for performance and safety.

What is the difference between this and the OEM part?

Functionally, there is no difference. Our aftermarket sensor is engineered to meet or exceed OEM specifications for fit, form, and function. It's made from comparable high-quality materials, like glass-filled polyester, to ensure durability in marine environments but is available at a more competitive price point.

What is the recommended replacement interval?

There is no fixed replacement interval for ignition sensors; they are typically replaced only when they fail. However, if you are performing a major ignition system overhaul (e.g., replacing the distributor cap, rotor, and wires), it can be preventative maintenance to replace the sensor as well.

Does this kit include everything I need for installation?

This kit includes the ignition sensor, lead wires with connectors, and a basic hardware kit with mounting screws. You will need your own standard hand tools to complete the installation. No other specialized components are required.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost?

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns?

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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